Radiofrequency Identification Exposure Research Articles

Influences of exposure to 915-MHz radiofrequency identification signals on serotonin metabolites in rats: a pilot study

Purpose The influences of radiofrequency electromagnetic exposure on animal health, particularly on serotonin metabolism, are not well-elucidated. In this in vivo study, we studied the influences of exposure to radiofrequency identification (RFID) signals on serotonin metabolism. Materials and methods Twenty-two male Sprague–Dawley rats were assigned to sham (n = 10) and RFID-exposed (n = 12) groups. Rats in the RFID-exposed group were exposed to RFID signals at an average whole-body specific absorption rate of 2 W/kg for 8 h/day, 5 days/week for 2 weeks. Before and after RFID exposure, 24-h urine was collected from each rat. Urinary tryptophan, 5-hydroxytryptophan, serotonin, 5-hydroxyindoleacetic acid, and 5-methoxyindole-3-acetic acid concentrations were examined using gas chromatography-mass spectrometry, and changes in the patterns of values were compared between the two groups. Results Urinary levels of serotonin decreased by 20% (p = .041, Student’s t-test) and 40% (p = .024, Student’s t-test) in both the sham and RFID-exposed groups, respectively. The level of 5-methoxyindole-3-acetic acid decreased by 30% in the RFID-exposed group (p = .039, Student’s t-test). Conclusion Our results indicate that exposure to RFID signals at a specific absorption rate of 2 W/kg is sufficient to alter serotonin metabolism in rats regardless of whether the exposure level is considered biohazardous.

Effects of exposure to electromagnetic field from 915 MHz radiofrequency identification system on circulating blood cells in the healthy adult rat.

We investigated whether exposure to the 915 MHz radiofrequency identification (RFID) signal affected circulating blood cells in rats. Sprague-Dawley rats were exposed to RFID at a whole-body specific absorption rate of 2 W/kg for 8 h per day, 5 days per week, for 2 weeks. Complete blood counts were performed after RFID exposure, and the CD4+ /CD8+ ratio was determined by flow cytometry. The number of red blood cells (RBCs) and the values of hemoglobin, hematocrit, and RBC indices were increased in the RFID-exposed group compared with those in the cage-control and sham-exposed groups (P < 0.05). However, the RBCs and platelet numbers were within normal physiologic response ranges. The number of white blood cells, including lymphocytes, was decreased in RFID-exposed rats. However, there was no statistically significant difference between the sham-exposed and RFID-exposed groups in terms of T-cell counts or CD4+ /CD8+ ratio (P > 0.05). Although the number of circulating blood cells was significantly altered by RFID exposure at a whole-body specific absorption rate of 2 W/kg for 2 weeks, these changes do not necessarily indicate that RFID exposure is harmful, as they were within the normal physiological response range. Bioelectromagnetics. 39:68-76, 2018. © 2017 Wiley Periodicals, Inc.

Eight hours of nocturnal 915 MHz radiofrequency identification (RFID) exposure reduces urinary levels of melatonin and its metabolite via pineal arylalkylamine N-acetyltransferase activity in male rats

Purpose: We investigated the effects of whole-body exposure to the 915 MHz radiofrequency identification (RFID) on mela-tonin biosynthesis and the activity of rat pineal arylalkylamine N-acetyltransferase (AANAT).Materials and methods: Rats were exposed to RFID (whole-body specific absorption rate, 4 W/kg) for 8 h/day, 5 days/week, for weeks during the nighttime. Total volume of urine excreted during a 24-h period was collected after RFID exposure. Uri-nary melatonin and 6-hydroxymelatonin sulfate (6-OHMS) was measured by gas chromatography-mass spectrometry (GC-MS) and enzyme-linked immunosorbent assay (ELISA), respectively. AANAT enzyme activity was measured using liquid biphasic dif-13 fusion assay. Protein levels and mRNA expression of AANAT was 14 measured by Western blot and reverse transcription polymerase 15 chain reaction (RT-PCR) analysis, respectively.Results: Eight hours of nocturnal RFID exposure caused a sig-nificant reduction in both urinary melatonin (p = 0. 003) and 6-OHMS (p = 0. 026). Activity, protein levels, and mRNA expres-sion of AANAT were suppressed by exposure to RFID (p < 0. 05).Conclusions: Our results suggest that nocturnal RFID exposure can cause reductions in the levels of both urinary melatonin and 6-OHMS, possibly due to decreased melatonin biosynthesis via suppression of Aanat gene transcription in the rat pineal gland.

Metabolomic study of urinary polyamines in rat exposed to 915 MHz radiofrequency identification signal

Metabolomic analysis of urinary polyamines (PAs) from rat exposed to 915 MHz radiofrequency identification (RFID) signal for 8 h/day for 2 weeks was performed by gas chromatography-mass spectrometry as N-ethoxycarbonyl/N-pentafluoropropionyl derivatives. Large alterations in nine PA levels including four aliphatic and five acetylated PAs were monitored in sham-exposed and RFID-exposed groups. Total PA and urinary levels of N (1)-acetylputrescine, N (1)-acetylcadaverine, putrescine, cadaverine, N (1)-acetylspermidine, N (8)-acetylspermidine, spermidine and spermine were reduced, whereas N (1)-acetylspermine was significantly increased after sham and RFID exposure compared with those before exposure. Their levels were normalized to the corresponding group means before exposure and then plotted into star symbol patterns. N (1)-Acetylspermine after RFID exposure was 54 % higher compared to the level before RFID exposure, while it was elevated by only 17 % in the sham group. The results suggest that 915 MHz RFID exposure may induce metabolic disturbance of PA. It may also elevate spermidine/spermine acetyltransferase (SSAT) activity. Thus, the present metabolic profiling combined with star pattern recognition method might be useful for understanding the complexity of biochemical events after exposure to RFID signal.

Effects of 915 MHz Radiofrequency Identification Electromagnetic Field Exposure on Neuronal Precursor Cells in the Dentate Gyrus of Adult Rat Brains

To explore the effects of radiofrequency electromagnetic field on the fate of neuronal cells, we investigated whether exposure to 915 MHz radiofrequency identification (RFID) caused morphological changes in neuronal cells in rat hippocampal dentate gyrus (DG). A reverberation chamber was used as a whole-body RFID exposure system. Rats were assigned to two groups: sham- and RFID-exposed groups. Rats in the RFID-exposed group were exposed to RFID at 4 W/kg specific absorption rate (SAR) for 8 hours daily, 5 days per week, for 2 weeks. Morphological evaluation of DG was performed using immunohistochemistry with doublecortin (DCX) as a neuronal precursor cell marker and neuronal nuclei (NeuN) as a mature neuronal cell marker. No significant morphological changes in DCX+ or NeuN+ cells in the DG of RFID-exposed rats were observed. These results suggest that RFID exposure induces no significant change in DCX+ neuronal precursor or NeuN+ neuronal cells in DG of rats.

Design of unique simulators to evaluate medical device susceptibility to radio frequency identification exposure

Background: The use of radiofrequency identification (RFID) in healthcare is increasing, but one of the biggest obstacles for widespread adoption is electromagnetic compatibility (EMC). Numerous studies have documented that RFID can interfere with medical devices. No recognized standard test methods currently exist to address medical device EMC from RFID emitters. This study identifies a potential protocol to test the effect of RFID exposure on medical devices. Methods: We developed four separate simulators which cover four distinct RFID frequency bands: Low frequency (LF): 125 kHz; High frequency (HF):13.56 MHz; Ultra high frequency (UHF): 915 MHz; and 2.4 GHz. The RFID Test Library includes actual RFID input signals and recommended field strength values for each simulator. The simulators consist of Helmholtz coils for LF and HF and use IEC 61000-4-3 exposure methods for UHF and 2.4 GHz. Discussion: The protocol presented in this paper represents oneway to test if your medical device could be affected from exposure to RFID readers. The antennas chosen are used to produce repeatable tests. The input signals and field strengths are chosen to represent a wide variety of actual RFID reader technologies. Summary: The protocol needs to be tested with actual medical devices to understand the effects of the varying RFID test signals and to determine if the RFID Test Library is adequately defined. These tests are currently being conducted independently by the Food and Drug Administration (FDA) and MET Laboratories. Suggested maximum field levels are calculated and presented as a reasonable worst case exposure. It is the intent that after test validation this protocol will be submitted to the Association for Automatic Identification and Mobility (AIM) for publication.

The effects of exposure to 915 MHz radiofrequency identification on cerebral glucose metabolism in rat: A [F-18] FDG micro-PET study

Purpose: We investigated the effect of whole-body exposure to 915-MHz radiofrequency identification (RFID) on rat cortical glucose metabolism by using 18F-deoxyglucose positron emission tomography (FDG-PET).Materials and methods: Male Sprague-Dawley rats were divided into three groups: Cage-control, sham-exposed and RFID-exposed groups. Rats were exposed to the 915-MHz RFID for 8 h daily, 5 days per week, for 2 or 16 weeks. The whole-body average specific absorption rate (SAR) was 4 W/kg for the field of the 915 MHz RFID signal. FDG-PET images were obtained the day after RFID exposure, using micro-PET with a FDG tracer. With a Xeleris functional imaging workstation, absolute values in regions of interest (ROI) in the frontal, temporal and parietal cortexes and cerebellum were measured. Cortical ROI values were normalized to the cerebellar value and compared.Results: The data showed that the relative cerebral glucose metabolic rate was unchanged in the frontal, temporal and parietal cortexes of the 915 MHz RFID-exposed rats, compared with rats in cage-control and sham-exposed groups.Conclusion: Our results suggest that 915 MHz RFID radiation exposure did not cause a significant long lasting effect on glucose metabolism in the rat brain.

Evaluation of Thermal and Nonthermal Effects of UHF RFID Exposure on Biological Drugs

The Radio Frequency Identification (RFID) technology promises to improve several processes in the healthcare scenario, especially those related to traceability of people and things. Unfortunately, there are still some barriers limiting the large-scale deployment of these innovative technologies in the healthcare field. Among these, the evaluation of potential thermal and non-thermal effects due to the exposure of biopharmaceutical products to electromagnetic fields is very challenging, but still slightly investigated. This paper aims to setup a controlled RF exposure environment, in order to reproduce a worst-case exposure of pharmaceutical products to the electromagnetic fields generated by the UHF RFID devices placed along the supply chain. Radiated powers several times higher than recommended by current normative limits were applied (10 W and 20 W). The electric field strength at the exposed sample location, used in tests, was as high as 100 V/m. Non-thermal effects were evaluated by chromatography techniques and in vitro assays. The results obtained for a particular case study, the ActrapidTM human insulin preparation, showed temperature increases lower than 0.5 °C and no significant changes in the structure and performance of the considered drug.

Time location analysis for exposure assessment studies of indoor workers based on active RFID technology

In this article, we describe the development of a radio frequency identification exposure monitoring system (RFEMS) suitable for tracking and identifying workers' locations in indoor workplaces. Five workers in southern Taiwan wore the RFEMS integrated into their equipment vests. Location and exposure data were transferred to data analysis software for visualization and tabular analysis in real-time. Data were grouped into seven task activity location categories to determine the time spent and percentage reception in each location. The RFEMS could also synchronously indicate the surrounding conditions using various sensors. Additional experiments were focused on locating of boundaries and determining the instrument stability, power sustainability, and reception efficiency in typical environments. The RFEMS instruments provided adequate range for locating (typically ca. 6-45 m in each zone), allowing us to locate subjects within distinct microenvironments and to distinguish between the activities of a variety of workers, the average time activity pattern (TAP) recording deviation for both human observations and RFEMS was ca. 0.21-1.57%. Power consumption experiments revealed that the system could be sustained for more than 124 h. A pilot field test indicated that the RFEMS offers a new level of accuracy for direct quantification of time activity patterns in exposure assessments of indoor workers over long periods of time.

Field evaluation of measuring indoor noise exposure in workplace with task-based active RFID technology

This paper describes the research using RFEMS (Radio Frequency Identification Exposure Monitoring System), which is designed by applying the task-based active RFID (radio frequency identification) technology, to measure the indoor noise exposure dose in a workplace. The RFEMS and sound level meter are mounted on the vests of eight workers to carry out on-site field test by monitoring the time activity pattern (TAP), and the noise dose level exposed by the workers. The data are recorded and instantaneously transmitted to a computer to be saved in the server and later compared to those obtained using the standard method. The results that have a 0.909 correlation coefficient (R(2)), and 1.64% average measure error confirm the accuracy of using RFEMS for monitoring TAP. Additionally, the combined use of RFEMS and sound level meter leads to the development of a semi noise dosimetry (SND), a real-time electronic indirect noise dosimetry (REIND), and an equivalent electronic recording indirect noise dosimetry (EEIND). The results obtained using these three devices are well correlated with the results monitored by using a PND (personal noise dosimetry) with correlation coefficients (R(2)) of 0.915, 0.779 and 0.873, respectively. The errors of noise dose expressed in TWA (time weight average) for these three methods are 0.81, 1.57 and 1.23 dBA, respectively; they are well within the general errors of the average dosimetries. These observations indicate that the RFEMS developed in this research is applicable for conducting task-based measurements of indoor noise. It uses a relatively inexpensive sound level meter to measure the noise exposure doses that are comparable to those obtained with a standard dosimetry in addition to monitoring the worker's time activity pattern. The findings will assist in studying the source of long-term noise exposed by workers, and hence this devise is a valuable tool for tracing and monitoring long-term noise exposure with reduced manpower requirements.

In vitro tests reveal sample radiofrequency identification readers inducing clinically significant electromagnetic interference to implantable pacemakers and implantable cardioverter-defibrillators

The use of radiofrequency identification (RFID) systems is expanding and highlights the need to address electromagnetic interference (EMI) to implantable pacemakers and implantable cardioverter-defibrillators (ICDs). This study sought to examine the electromagnetic compatibility (EMC) between RFID readers and implantable pacemakers or ICDs. During in vitro testing, 15 implantable pacemakers and 15 ICDs were exposed to 13 passive RFID readers in 3 frequency bands: 134 kHz (low frequency [LF]), 13.56 MHz (high frequency [HF]), and 915 MHz (ultra high frequency [UHF]). While being exposed to LF RFID, a reaction was observed for 67% of all pacemaker tests (maximum distance 60 cm) and 47% of all ICD tests (maximum distance 40 cm). During HF RFID exposure, a reaction was observed for 6% of all pacemaker tests (maximum distance 22.5 cm) and 1% of all ICD tests (maximum distance 7.5 cm). For both pacemakers and ICDs, no reactions were observed during exposure to UHF RFID or continuous-wave RFID. Pacemakers and ICDs were most susceptible to modulated LF RFID readers. Although there is in vitro testing evidence for concern for implantable pacemaker and ICD EMI at LF and HF, the FDA has not received any incident reports of pacemaker or ICD EMI caused by any RFID system. We do not believe the current situation reveals an urgent public health risk.

In vitro Assessment of Electromagnetic Interference due to Low-Band RFID reader/writers on Active Implantable Medical Devices

Introduction: The electromagnetic interference (EMI) of active implantable medical devices (AIMDs) due to 125–135 kHz and HF (13.56MHz) radio-frequency identification (RFID) reader/writers are discussed based on in vitro experiments. The purpose of this paper is to clarify the detailed EMI occurrence conditions of both implantable cardiac pacemakers and implantable cardioverter defibrillators (ICDs) when used in proximity to commercial lowband RFID reader/writers. Methods and results: A total of 20 types of pacemakers and 7 types of ICDs from 9 manufacturers are used in the experiments. The tested RFID reader/writers are 4 types of 125–135 kHz antennas and 26 types of HF antennas. The test system is newly constructed based on the one previously proposed for the estimation of EMI due to mobile phones. The measured reactions are missing of pacing pulses and generation of asynchronous pulses for pacemaker functions and inappropriate tachyarrhythmia detection and delivery of therapy for ICDs. In addition, measured EMI characteristics strongly depend on intermittent period of RFID signals. However, all AIMDs tested return to normal operation once removed from RFID exposure. Conclusion: The detailed EMI characteristics of AIMDs and low-band RFID reader/ writers are obtained to prevent adverse interactions.